1. Field of the Invention
The present invention relates to signal processing apparatuses and methods for performing gain control so that a target gain can be obtained for each of a predetermined number of frequency bands of an input signal.
2. Description of the Related Art
In the related art, a known example of an effecter for changing a frequency-amplitude characteristic of an audio signal is a graphic equalizer (GEQ). One known example of such a GEQ has an operation element for each equalizer element which can be operated by a user to set a gain for a corresponding frequency band.
In recent years, a GEQ including an automatic sound-field correcting function in which various sound-field corrections, such as correction of a frequency-amplitude characteristic, are performed automatically has been used in, for example, a car audio system or a home audio visual (AV) system.
In this system, a microphone is set at a listening position in advance, a test signal output from a speaker is picked up by the microphone, and the frequency-amplitude characteristic thereof is measured on the basis of the picked-up test signal. Signal processing is performed on an audio signal on the basis of the measurement result so that a target frequency-amplitude characteristic can be obtained. Specifically, gains set to equalizer elements for corresponding frequency bands are controlled so that the target characteristics can be obtained by using the above-described GEQ, for example.
Japanese Unexamined Patent Application Publication No. 8-047079, for example, discloses the related art.